textproduct: Albany

WHAT HAS CHANGED

Heat Advisory issued for eastern Ulster, western Dutchess and southern Litchfield Counties from 11 AM Thursday through 8 PM Friday.

KEY MESSAGES

1) Scattered to numerous showers and thunderstorms return for the end of the work week, bringing the potential for locally heavy rain and isolated damaging wind gusts, particularly on Thursday.

2) Increasing heat and humidity also return Thursday into Friday, which may result in heat-related impacts, mainly in eastern Ulster, western Dutchess and southern Litchfield CT.

DISCUSSION

KEY MESSAGE 1...

Deep layer moisture and humidity increases Thu into Fri, as a southwest flow continues around the periphery of a Bermuda high in the western Atlantic. Dewpoints will likely rise into the lower 70s to mid 70s(southern areas), with PWAT anomalies increasing to +1 to +3 STDEV(from NAEFS). Convection will be most likely during the diurnally favored afternoon through early evening hours. Synoptic scale forcing still looks fairly weak much of the time, as a frontal system will be positioned north/west of Lake Ontario. The front will only make slow/gradual southeast progress due to the Bermuda high in place. Will continue to cap PoPs at 60-70% Thu and Fri. Both days should not be washouts, although scattered to numerous showers/T- storm are expected to develop in the afternoon.

SBCAPE forecast from the REFS looks more robust now, with potentially 2000-3000 J/Kg from around the Capital District south along with 0-6 km shear of 25-30 kt. This environment is conducive for some severe storms, although lack of significant forcing is a mitigating factor along with fairly weak mid level lapse rates. The main threat would be isolated damaging wind gusts due to precip loading. The Storm Prediction Center continues to have a Marginal Risk (level 1 of 5) outlook from around the Mohawk Valley and Saratoga region south and west.

AI NWP convective hazards forecast continues to show potential for some severe storms Fri, especially from Albany south/east. Based on the latest CAMs, timing looks to be later in the day into the evening. CAPE looks similar to Thu, although shear may be a bit weaker. With high PWATs continuing, there is potential for isolated wet microbursts. Will continue to monitor trends.

Also with a humid/moist environment and wet antecedent ground conditions in place, there is the potential for isolated flash flooding where persistent or repeated downpours occur. There is a Marginal Risk (level 1 of 4) of excessive rainfall both Thu and Fri.

The front may finally start to settle south/east across the area on Sat, with additional showers/T-storms again mainly in the afternoon to early evening hours. Again, storms may produce gusty winds and locally heavy rainfall. A small area of high pressure builds in on Sun, providing drier conditions.

KEY MESSAGE 2...

With our region positioned along the northwest periphery of the Bermuda high, increasing heat and humidity will occur Thu into Fri. Although high temperatures will likely remain below 90F, dewpoints rising into the lower/mid 70s will still result in heat indices(feels-like temperatures) in the mid to upper 90s in southern portions of the mid Hudson Valley and southern Litchfield CT both days. A Heat Advisory has been issued for these few zones late Thu morning through early Fri evening. In valley locations outside of the advisory area, peak heat indices will mainly in the lower 90s.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

VFR conditions continue through 06/06z for all TAF sites with variable wind directions and speeds between 5 and 10 knots through this afternoon. By 06/00z, winds decrease to light and variable to calm for the overnight hours into tomorrow morning. Between 06/06z and 06/12z, ceilings could lower to between IFR/MVFR with confidence higher for MVFR ceilings through the end of the TAF period. A TEMPO group has been added for IFR/LIFR ceilings at KPSF from 8z to 12z. After 12z, MVFR and VFR conditions should fluctuate due to passing low clouds. For KPOU, included PROB30 groups for low chances of isolated light rain showers from 3Z to 12Z. For KGFL, KALB, and KPSF, removed PROB30 groups as confidence is increasing for no visibility impacts from rain showers as shower activity is trending to be further south for tonight into early tomorrow morning.

Outlook...

Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Friday: High Operational Impact. Likely SHRA...TSRA. Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Saturday: High Operational Impact. Likely SHRA...TSRA. Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday: Low Operational Impact. Slight Chance of SHRA. Sunday Night: Low Operational Impact. Slight Chance of SHRA. Monday: Moderate Operational Impact. Chance of SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...Heat Advisory from 11 AM Thursday to 8 PM EDT Friday for CTZ013. NY...Heat Advisory from 11 AM Thursday to 8 PM EDT Friday for NYZ064-065. MA...None. VT...None.